Text 0.5.0 bktree overhamming - CyrilB1531/lodestar GitHub Wiki

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BkTree.OverHamming

Builds an empty tree over Hamming.Distance.

public static BkTree OverHamming(TextElement element = TextElement.Utf16Unit)

Parameterselement says what counts as one character: TextElement.Utf16Unit by default, or TextElement.CodePoint outside the Basic Multilingual Plane.

Returns — an empty BkTree.

Example — one differing position.

using Lodestar.Text.Indexing;

BkTree tree = BkTree.OverHamming();
tree.AddRange(["1010", "1011", "0000"]);
int found = tree.WithinDistance("1010", 1).Count;   // => 2

Remarks — Lodestar's Hamming is not textbook Hamming: it adds the absolute length difference rather than refusing unequal lengths. That variant had to be checked rather than assumed, and it satisfies the triangle inequality — zero violations over every triple of words up to length 4 on a three-letter alphabet and up to length 6 on a two-letter one.

Positional by nature, so it suits fixed-width codes — identifiers, hashes, fingerprints — far better than words, where a single insertion shifts every later character and inflates the distance.

Applies to — net10.0, netstandard2.0.

See alsoBkTree, Hamming.Distance.